This is an important question from the
Book- ML Aggarwal
Board- ICSE
Publication- Avichal
Chapter- Trigonometric Identities
Chapter number-18
If x – a sec θ + b tan θ and y = a tan θ + b sec θ, prove that x2 – y2 = a2 – b2.
Trigonometric Identities, class 10th, chapter 18th, question no34 , ICSE board, ML aggarwal..
Given,
x =
a sec θ + b tan θ,
y = a tan θ + b sec θ
Now,
x2 – y2 = (a sec θ + b tan θ)2 – (a tan θ + b sec θ)2
– Hence proved.